1. Field of the Invention
This invention relates to a function liquid filling apparatus which fills passages inside a function liquid droplet ejection head with a function liquid contained in a function liquid tank by feeding the function liquid into a head cap side through the function liquid droplet ejection head. This invention also relates to a liquid droplet ejection apparatus equipped with the function liquid filling apparatus; a method of manufacturing an electro-optical device; an electro-optical device; and an electronic equipment.
2. Description of the Related Art
An ink jet head (function liquid droplet ejection head) of an ink jet printer (liquid droplet ejection apparatus) can accurately eject minute ink droplets (liquid droplets) in a dot shape. Thus, the ink jet head is expected to be applied to the field of manufacturing various products. There has been considered a liquid droplet ejection apparatus which introduces a function liquid, such as a particular link and a photosensitive resin liquid, into a function liquid droplet ejection head and accurately ejects the function liquid to a workpiece such as a substrate. In an initial stage of installation of a new apparatus or in the case of introducing a new function liquid droplet ejection head, passages inside the function liquid droplet ejection head are filled with a function liquid by using the following methods, i.e.: a method of driving suction means (a suction pump) which is connected to a head cap by connecting the head cap to the function liquid droplet ejection head; a method of driving pressurization feed means which is connected to a function liquid tank; and the like.
For example, in the method using the suction pump, the suction pump is driven to suck the function liquid from the function liquid tank through the function liquid droplet ejection head and the head cap. Thereafter, the function liquid is detected by detection means provided near a downstream side of the head cap, and the suction pump is stopped. In this case, as the detection means, there has been known one which detects the function liquid passing through transparent ducts, which are arranged in the downstream of the head cap, from the outside by using photosensors provided in the middle of the transparent ducts.
However, in an example in which an optical detection means such as the photosensor is used, malfunction is likely to occur when a dried function liquid is stuck to an inner surface of a pipe or passage of a member transmitting light or when dust and the like are adhered to an external surface of the pipeline or passage. Consequently, there arises a problem in that reliability of detection is deteriorated.